1. Field of the Invention
The present invention relates to a jig for fixedly holding a dual-side mounting PC board on a board table by suction when mounting a component on one side of the PC board with components already mounted on the other side thereof.
2. Description of the Prior Art
FIG. 31 is a plan view showing a PC board with components of the same size mounted on one side thereof; FIG. 32 is a plan view showing a conventional jig for dual-side mounting PC boards; FIG. 33 is a sectional view taken on the line 33--33 in FIG. 32; FIG. 34 is a sectional view taken on the line 34--34 in FIG. 32; FIG. 35 is a sectional view taken on the line 35--35 in FIG. 32 for explaining how to fixedly hold the PC board by suction; FIG. 36 is a plan view showing another PC board of a different component mounting layout; FIG. 37 is a plan view showing another conventional jig for dual-side mounting PC board depicted in FIG. 36; FIG. 38 is a sectional view taken on the line 38--38 in FIG. 37; FIG. 39 is a sectional view taken on the line 39--39 in FIG. 37; FIG. 40 is a sectional view taken on the line 40--40 in FIG. 37; FIG. 41 is a sectional view taken on the line 38--38 in FIG. 37 for explaining how to fixedly hold the PC board by suction; FIG. 42 is a sectional view taken on the line 39--39 in FIG. 37 for explaining how to fixedly hold the PC board by suction; FIG. 43 is a plan view showing a PC board with components of different sizes mounted on one side thereof; FIG. 44 is a plan view showing another conventional jig corresponding to the PC board depicted in FIG. 43; FIG. 45 is a sectional view taken on the line 45--45 in FIG. 44; FIG. 46 is a sectional view taken on the line 46--46 in FIG. 44; FIG. 47 is a sectional view taken on the line 47--47 in FIG. 44; FIG. 48 is a sectional view taken on the line 45--45 in FIG. 44 for explaining how to fixedly hold the PC board by suction; FIG. 49 is a sectional view taken on the line 46--46 in FIG. 44 for explaining how to fixedly hold the PC board.
In the drawings, reference numeral 31 denotes surface mounting components of the same size mounted on a PC board 32; reference numeral 33 denotes a PC board table for supporting the PC board 32 on its top or board supporting surface 33a; reference numeral 34 denotes component receiving holes made in the board supporting surface 33a of the table 33 to receive the surface mounting components 31.
Reference numeral 36 denotes a platform for supporting the board table 33 mounted thereon, which is provided with an upwardly opening space 37 for vacuum suction and an evacuating port 38 that communicates with the vacuum-sucking space 37 and is connected to a vacuum pump or the like though not shown. When the PC board table 33 is placed on the platform 36, the vacuum-sucking space 37 forms a closed space, which is evacuated to a vacuum by the vacuum pump or the like via the evacuating port 38.
Reference numeral 39 denotes PC board sucking holes bored through the board table 33 and communicating with the vacuum-sucking space 37 as shown in FIGS. 34, 40 and 47.
Next, a description will be given first, with reference to FIGS. 35, 41 and 42, of the operation for fixing the PC board 32, shown in FIG. 31 and 36, to the board table 33 by suction.
In the first place, the PC board 32 is placed on the board table 33 with the surface mounting components 31 snugly received in the component receiving holes 34, the board sucking holes 39 being covered with the PC board 32.
As the vacuum-sucking space 37 is evacuated by a vacuum pump or the like connected to the evacuating port 38 of the platform 36, the pressure in the space 37 is reduced, and consequently, the PC board 32 is fixed to the top 33a of the board table 33 by the forces of attraction through the board sucking holes 39.
The underside areas of the PC board 32 where no components are mounted are supported by those areas of the table top 33 surrounding the component receiving holes 34. This prevents that when new components are mounted on the other side of the PC board 32 afterward, excessive pressure is applied to the already mounted components 31 or the PC board 32 is bent, often resulting in the breakage of the board 32 or lead wires.
Next, a description will be given, with reference to FIGS. 48 and 49, of fixing the PC board 32 of FIG. 43 to the board table 33 by suction.
The PC board 32 is placed on the board table 33 with components 31 and 31a snugly received in component receiving holes 34 and 34a and covers the board sucking holes 39. Then the PC board 32 is fixed to the board table 33 by suction in the same fashion as described above.
Also in this instance, the underside areas of the PC board 32 where no components are mounted are supported by those areas of the table top 33 surrounding the component receiving holes 34 and 34a. The subsequent mounting of components on the other side of the PC board 32 will not exert any excessive pressure to the already mounted components 31 and 31a nor will it bend the PC board 32 to such an extent as to break it or lead wires formed thereon.
Incidentally, the techniques for supporting dual-side mounting PC boards are disclosed in JP-A-2-94591 and a method for mounting components is set forth in JP-A-61-288490.